/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/DynamicMesh3.h
Copy input mesh while compacting, i.e. removing unused vertices/triangles/edges. Note that it is currently unsafe to hold on to the attribute set pointer (returned fromAttributes()) across the CompactCopy call, as the latter may rebuild an entirely new attribute set.
void CompactCopy ( const [FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) & CopyMesh, bool bNormals, bool bColors, bool bUVs, bool bAttributes, [FCompactMaps](API\Runtime\GeometryCore\Util\FCompactMaps) * CompactInfo )